DIMETHYLALUMINUM CHLORIDE CATALYZED ENE REACTIONS OF ALDEHYDES
DIMETHYLALUMINUM CHLORIDE CATALYZED ENE REACTIONS OF ALDEHYDES
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DOI：
10.1021/ja00366a031
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发表时间：
1982-01-01
影响因子：
15
通讯作者：
CORDOVA, R
中科院分区：
文献类型：
--
作者：
SNIDER, BB;RODINI, DJ;CORDOVA, R
二甲基氯化铝是一种温和的路易斯酸和质子清除剂，催化脂肪和芳香醛与含有二取代乙烯基碳的烯烃的烯反应。质子引发的重排不会发生，因为在烯反应中形成的醇-路易斯酸络合物反应迅速，生成甲烷和非酸性的铝烷氧化物。甲醛和过量的Me2AlCl对所有类型的烯烃的烯加合物都有很好的收率。用1等量的Me2AlCl、甲醛和单取代烯烃和1,2 -二取代烯烃在双键上顺式加成氯和羟甲基而生成氯醇。羰基化合物与烯烃的烯反应是合成同丙烯醇的一条潜在的有价值的途径。2对于反应性的，即缺乏电子的醛类，如氯醛或乙醛甲酯，这些反应可以在100-200℃的高温下进行。3,4甲醛与烯烃在180℃下反应，以乙酸-乙酸酐为溶剂时，通常可获得最佳产率。5
Dimethylaluminum chloride, which is a mild Lewis acid and a proton scavenger, catalyzes the ene reactions of aliphatic and aromatic aldehydes with alkenes containing a disubstituted vinylic carbon. Proton-initiated rearrangements do not occur, since the alcohol-Lewis acid complex formed in the ene reaction reacts rapidly to give methane and a nonacidic aluminum alkoxide. Formaldehyde and excess Me2AlCl give good yields of ene adducts with all types of alkenes. With 1 equiv of Me2AlCl, formaldehyde and mono- and 1, 2-disubstituted alkenes give-chloro alcohols resulting from cis additionof chlorine and hydroxymethyl groupsto the double bond.The ene reaction of carbonylcompounds with alkenes isa potentially valuable route to homoallylic alcohols. 2 With reactive, ie, electrondeficient, aldehydes such as chloral or methyl glyoxylate, these reactions can be carried out thermally at 100-200 C. 3, 4 Formaldehyde reacts with alkenes at 180 C with optimal yields often being obtained when acetic acid-acetic anhydride is the solvent. 5